Question 1

The margin of error is one-half the width of the confidence interval.

Accepted Answer

A) True 
 B)False

Question 2

In a recent audit report,an accounting firm stated that the mean sale per customer for the client was estimated to be between $14.50 and $28.50.Further,this was based on a random sample of 100 customers and was computed using 95 percent confidence.Provide a correct interpretation of this confidence interval estimate.

Accepted Answer

A correct interpretation is: "

Question 3

A study was recently conducted to estimate the mean cholesterol for adult males over the age of 55 years.From a random sample of n = 10 men,the sample mean was found to be 242.6 and the sample standard deviation was 73.33.To find the 95 percent confidence interval estimate for the mean,the correct critical value to use is:

Accepted Answer

A) 1.96. 
B) 2.2281. 
C) 2.33. 
D) 2.2622. 
A) 1.96. 
B) 2.2281. 
C) 2.33. 
D) 2.2622.

Question 4

When σ is unknown,the margin of error is computed by using

Accepted Answer

A) normal distribution. 
B) t-distribution. 
C) the mean of the sample. 
D) The margin of error is also unknown. 
A) normal distribution. 
B) t-distribution. 
C) the mean of the sample. 
D) The margin of error is also unknown.

Question 5

In an effort to estimate the mean dollars spent per visit by customers of a food store,the manager has selected a random sample of 100 cash register receipts.The mean of these was $45.67 with a sample standard deviation equal to $12.30.Assuming that he wants to develop a 90 percent confidence interval estimate,the upper limit of the confidence interval estimate is:

Accepted Answer

A) about $2.02. 
B) approximately $65.90. 
C) about $47.69. 
D) None of the above. 
A) about $2.02. 
B) approximately $65.90. 
C) about $47.69. 
D) None of the above.

Question 6

After taking a speed-reading course,students are supposed to be able to read faster than they could before taking the course.A pilot sample of n = 25 students showed a mean increase of 300 words per minute with a standard deviation equal to 60 words per minute.To estimate the population mean with 95 percent confidence and a margin of error of ± 10 minutes,the required sample size is approximately 139 students.

Accepted Answer

A) True 
 B)False

Question 7

When a decision maker determines the required sample size for estimating a population mean,a change in the confidence level will result in a change in the required sample size,provided that the margin of error is also modified accordingly.

Accepted Answer

A) True 
 B)False

Question 8

An educational organization in California is interested in estimating the mean number of minutes per day that children between the age of 6 and 18 spend watching television per day.A previous study showed that the population standard deviation was 21.5 minutes.The organization selected a random sample of n = 200 children between the ages of 6 and 18 and recorded the number of minutes of TV that each person watched on a particular day.The mean time was 191.3 minutes.If the leaders of the organization wish to develop an interval estimate with 98 percent confidence,what critical value should be used?

Accepted Answer

A) z = 1.645 
B) t = 2.38 
C) Approximately z = 2.33 
D) Can't be determined without knowing the margin of error. 
A) z = 1.645 
B) t = 2.38 
C) Approximately z = 2.33 
D) Can't be determined without knowing the margin of error.

Question 9

The margin of error is:

Accepted Answer

A) the largest possible sampling error at a specified level of confidence. 
B) the critical value times the standard error of the sampling distribution. 
C) Both A and B 
D) the difference between the point estimate and the parameter. 
A) the largest possible sampling error at a specified level of confidence. 
B) the critical value times the standard error of the sampling distribution. 
C) Both A and B 
D) the difference between the point estimate and the parameter.

Question 10

The administrator at Sacred Heart Hospital is interested in estimating the proportion of patients who are satisfied with the meals at the hospital.A random sample of 250 patients was selected and the patients were surveyed.Of these,203 indicated that they were satisfied.Based on this,what is the estimate of the standard error of the sampling distribution?

Accepted Answer

A) 0.8120 
B) 0.0247 
C) 0.0006 
D) Can't be determined without knowing σ. 
A) 0.8120 
B) 0.0247 
C) 0.0006 
D) Can't be determined without knowing σ.

Question 11

In discussing a confidence interval estimate for a population mean,is it acceptable to provide an interpretation like the following: "There is a 95 percent chance that μ lies in the range 20 to 40"?

Accepted Answer

No,this interpretation is not correct.As

Question 12

In a situation where the population standard deviation is known and we wish to estimate the population mean with 90 percent confidence,what is the appropriate critical value to use?

Accepted Answer

A) z = 1.96 
B) z = 2.33 
C) z = 1.645 
D) Can't be determined without knowing the degrees of freedom. 
A) z = 1.96 
B) z = 2.33 
C) z = 1.645 
D) Can't be determined without knowing the degrees of freedom.

Question 13

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this sample information,what is the point estimate for the proportion of people in Chicago that listen to WJKT-1450?

Accepted Answer

A) 340 
B) About 0.194 
C) 1450 
D) 66 
A) 340 
B) About 0.194 
C) 1450 
D) 66

Question 14

The general format for a confidence interval is:

Accepted Answer

A) point estimate ± z (standard deviation). 
B) point estimate ± (critical value)(standard error). 
C) margin of error ± (confidence coefficient)(standard error). 
D) point estimate ± (critical value)(standard deviation) 
A) point estimate ± z (standard deviation). 
B) point estimate ± (critical value)(standard error). 
C) margin of error ± (confidence coefficient)(standard error). 
D) point estimate ± (critical value)(standard deviation)

Question 15

In developing a confidence interval estimate for the population mean,which of the following is true?

Accepted Answer

A) The larger the sample standard deviation,the wider will be the interval estimate,all other things being equal. 
B) If the population standard deviation is unknown,the appropriate critical value should be obtained from the t-distribution. 
C) The confidence interval developed from a smaller sample size will have a larger margin of error than one obtained using a larger sample size,all other things being equal. 
D) All of the above are true. 
A) The larger the sample standard deviation,the wider will be the interval estimate,all other things being equal. 
B) If the population standard deviation is unknown,the appropriate critical value should be obtained from the t-distribution. 
C) The confidence interval developed from a smaller sample size will have a larger margin of error than one obtained using a larger sample size,all other things being equal. 
D) All of the above are true.

Question 16

Which of the following will result in a larger margin of error in an application involving the estimation of a population mean?

Accepted Answer

A) Increasing the sample size 
B) Decreasing the confidence level 
C) Increasing the sample standard deviation 
D) All of the above. 
A) Increasing the sample size 
B) Decreasing the confidence level 
C) Increasing the sample standard deviation 
D) All of the above.

Question 17

A confidence interval will contain the true population value as long as the point estimate is within the lower to upper limits.

Accepted Answer

A) True 
 B)False

Question 18

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this information,what is the upper limit for the 95 percent confidence interval estimate for the proportion of people in Chicago that listen to WJKT-1450?

Accepted Answer

A) 1.96 
B) Approximately 0.0009 
C) About 0.2361 
D) About 0.2298 
A) 1.96 
B) Approximately 0.0009 
C) About 0.2361 
D) About 0.2298

Question 19

A cell phone service provider has selected a random sample of 20 of its customers in an effort to estimate the mean number of minutes used per day.The results of the sample included a sample mean of 34.5 minutes and a sample standard deviation equal to 11.5 minutes.Based on this information,and using a 95 percent confidence level:

Accepted Answer

A) the critical value is z = 1.96. 
B) the critical value is z = 1.645. 
C) the critical value is t = 2.093. 
D) The critical value can't be determined without knowing the margin of error. 
A) the critical value is z = 1.96. 
B) the critical value is z = 1.645. 
C) the critical value is t = 2.093. 
D) The critical value can't be determined without knowing the margin of error.

Question 20

All of the factors that are needed to determine the required sample size are within the control of the decision maker.

Accepted Answer

A) True 
 B)False

The margin of error is one-half the width of the confidence interval.

When σ is unknown,the margin of error is computed by using

When a decision maker determines the required sample size for estimating a population mean,a change in the confidence level will result in a change in the required sample size,provided that the margin of error is also modified accordingly.

The margin of error is:

In discussing a confidence interval estimate for a population mean,is it acceptable to provide an interpretation like the following: "There is a 95 percent chance that μ lies in the range 20 to 40"?

In a situation where the population standard deviation is known and we wish to estimate the population mean with 90 percent confidence,what is the appropriate critical value to use?

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this sample information,what is the point estimate for the proportion of people in Chicago that listen to WJKT-1450?

The general format for a confidence interval is:

In developing a confidence interval estimate for the population mean,which of the following is true?

Which of the following will result in a larger margin of error in an application involving the estimation of a population mean?

A confidence interval will contain the true population value as long as the point estimate is within the lower to upper limits.

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this information,what is the upper limit for the 95 percent confidence interval estimate for the proportion of people in Chicago that listen to WJKT-1450?

All of the factors that are needed to determine the required sample size are within the control of the decision maker.

The Where, why, and How of Data Collection

Graphs,charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Using Probability and Probability Distributions

Discrete Probability Distributions

Introduction to Continuous Probability Distributions

Introduction to Sampling Distributions

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Multiple Regression Analysis and Model Building

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

Introduction to Decision Analysis

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Exam 8: Estimating Single Population Parameters

The margin of error is one-half the width of the confidence interval.

When σ is unknown,the margin of error is computed by using

When a decision maker determines the required sample size for estimating a population mean,a change in the confidence level will result in a change in the required sample size,provided that the margin of error is also modified accordingly.

The margin of error is:

In discussing a confidence interval estimate for a population mean,is it acceptable to provide an interpretation like the following: "There is a 95 percent chance that μ lies in the range 20 to 40"?

In a situation where the population standard deviation is known and we wish to estimate the population mean with 90 percent confidence,what is the appropriate critical value to use?

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this sample information,what is the point estimate for the proportion of people in Chicago that listen to WJKT-1450?

The general format for a confidence interval is:

In developing a confidence interval estimate for the population mean,which of the following is true?

Which of the following will result in a larger margin of error in an application involving the estimation of a population mean?

A confidence interval will contain the true population value as long as the point estimate is within the lower to upper limits.

A random sample of 340 people in Chicago showed that 66 listened to WJKT-1450,a radio station in South Chicago Heights.Based on this information,what is the upper limit for the 95 percent confidence interval estimate for the proportion of people in Chicago that listen to WJKT-1450?

All of the factors that are needed to determine the required sample size are within the control of the decision maker.

The Where, why, and How of Data Collection

Graphs,charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Using Probability and Probability Distributions

Discrete Probability Distributions

Introduction to Continuous Probability Distributions

Introduction to Sampling Distributions

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Multiple Regression Analysis and Model Building

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

Introduction to Decision Analysis

Filters